Coupling for optical-fiber connectors

ABSTRACT

A coupling ( 1 ) for receiving at least two plug-in connectors ( 2 ) which are joined to glass fiber cables, comprising at least one moveable cover ( 14 ) which is associated with a sheath opening ( 121 ), said cover covering the opening ( 121 ) of the sheath in a first position, and being able to be moved into a second position by introducing a plug-in connector ( 2 ), whereupon the cover ( 14 ) releases the opening ( 121 ) in the sheath, said cover ( 14 ) comprising a bent metallic leaf spring ( 141 ) and said leaf spring ( 141 ) being unstressed in the first position and the curvature of the leaf spring ( 141 ) being selected in such a way that a ferrule ( 23 ) of the plug-in connector ( 2 ) never comes into contact with the leaf spring ( 141 ) during the insertion process.

The invention relates to a coupling for accommodating plug-in connectorsaccording to the preamble of patent claim 1.

It is known for optical fibers to be connected coaxially to plug-inconnectors by means of couplings. The plug-in connectors are designedwith a ferrule at the free end for the purpose of central fixing. Thetwo ferules of the plugs which are to be connected can be introducedinto a sleeve of the corresponding coupling, the ferrules coming intocontact at the end surfaces. The sleeve is mounted in a sleeve mount.The outer shape of the coupling housing is defined by way of the givengeometries of a known installation opening. Light waves are transmittedby fiber-optic cables. In order to prevent the emission of harmful laserradiation when the plug is subjected to pulling on one side, aprotective device is necessary.

A coupling with a protective device is known, for example, from EP 0 599784 A1, there being arranged in front of the sleeve opening, as seen inthe plug-in direction, a moveable protective flap which, in a closedposition, at least partially overlaps the sleeve opening and, in orderfor the contact pin to be plugged in, can be moved into an openposition, the device having an inner bushing housing which can be pushedinto an outer bushing housing, and the protective flap being retained,and mounted pivotably, between the two bushing housings. Thedisadvantage with such a protective device is the amount of space takenup by the pivoting mechanism, with the result that it cannot be realizedwith small outer dimensions of the coupling. In addition, thehigh-outlay mechanism is cost-intensive to produce.

The invention is thus based on the technical problem of providing acoupling which is intended for accommodating plug-in connectorsconnected to fiber-optic cables and which, with small outer dimensionsof the coupling, provides protection against the emission of harmfullaser radiation and can be produced cost-effectively.

The problem is solved by the subject matter having the features of claim1. Further advantageous configurations of the invention can be gatheredfrom the subclaims.

The emission of harmful laser radiation from a sleeve opening of a plugreceptacle can be prevented by a covering assigned to the same, thecovering comprising a bent metallic leaf spring which, in a first,non-loaded position, covers the sleeve opening and, by the introductionof a plug into the plug receptacle, can be moved into a second position,the sleeve opening being free in the second position, and the bending ofthe leaf spring being selected such that the ferrule does not come intocontact with the leaf spring at any point in time during the plug-inoperation. The leaf spring is to be selected here such that there is noneed for any unnecessary application of force for the plug-in operation,and pronounced loading of the plug on account of the force of the leafspring in the plugged-in state is avoided. At the same time, theelasticity of the leaf spring ensures that, when the plug is subjectedto pulling, reliable return into the non-loaded position takes place. Ametallic covering of the sleeve opening is distinguished by good thermalstability. Moreover, the metallic leaf spring allows a very thinconfiguration of the covering, although the sleeve opening is shieldedto good effect. Even colored plastic flaps for covering the sleeveopening require a considerably thicker configuration. In order, in thiscase, not to obstruct the plug from being accommodated by the covering,a change in the outer shape of the coupling housing is necessary.Changes in the outer shape, however, are undesirable for the purpose ofensuring compatibility with the standard or that further couplings canbe added on in a compact manner.

In a preferred embodiment, the covering is formed integrally with a leafspring and two wings. Via the wings, the covering can be attachedtangentially to a housing wall, the movement of the leaf spring beingdisrupted as little as possible by this attachment. The wings here arelimited by the maximum outer dimensions of the coupling.

In one development, the means for accommodating the covering is designedas a separate connection piece which can be connected to the couplinghousing. This makes it possible for the connection piece and thecoupling housing to be produced separately. This is advantageous since,for example, the material can be selected in accordance with therespective requirements. It is also conceivable for couplings to be usedin situations where they do not require any protective device againstthe emission of laser light. A two-part configuration of the protectivedevice and of the coupling housing allows specific use of the protectivedevice. A single-piece embodiment, however, is more stable and may thusbe necessary for specific applications.

In one embodiment, the covering is fastened tangentially to the housingwall by hot stamping. The hot-stamping attachment can be realizedcost-effectively. In addition, it is possible to produce the attachmentboth in the case of a single-piece configuration and in the case of atwo-part configuration of the coupling housing and of the connectionpiece from plastic.

In a preferred embodiment, the connection piece is designed as a plasticpart, it being possible for the covering to be connected to theconnection piece by injection-molding encapsulation. This makes itpossible to realize very good attachment of the covering to theconnection piece.

In a further embodiment, the connection piece is designed as a separatesheet-metal part, the covering, configured as a leaf spring, beingintegrated in the sheet-metal part. Various methods such as spot weldingor adhesive bonding are conceivable for attaching the leaf spring to theconnection piece. The configuration of the connection piece as asheet-metal part provides a higher stability than a plasticconfiguration.

In one development, the connection piece is formed integrally with thecovering. This development is distinguished by particular stability.

In a preferred embodiment, the connection piece is attached to thecoupling housing by a latching fastening. A latching fastening isadvantageous since, on the one hand, automated installation can easilybe realized but, on the other hand, it is also possible to provide areleasable connection. This makes it possible for the couplings to beadapted specifically to the respective use.

In a further embodiment, the connection piece is designed, for secureattachment, with centering pins.

The invention is explained in more detail hereinbelow with reference toa preferred exemplary embodiment. In the figures, schematically in eachcase:

FIG. 1 shows a plan view of a coupling for coaxial optical-fiberconnection and of a plug-in connector,

FIG. 2 shows a section through the plan view shown in FIG. 1,

FIG. 3 shows a perspective illustration of a coupling housing and of aconnection piece,

FIG. 4 shows a perspective illustration of the connection piece,

FIG. 5 shows a perspective illustration of a covering,

-   -   FIGS. 6( a)-(c) show sectional illustrations of the coupling and        of the plug-in connector during the plug-in operation,

FIG. 7 shows a perspective illustration of a first embodiment of adust-protection cap, and

FIG. 8 shows a perspective illustration of a second embodiment of thedust-protection cap.

FIG. 1 shows, schematically, a coupling 1 for the coaxial connection offiber-optic cables. The coupling comprises a coupling housing 10 intowhich a plug-in connector 2 can be plugged in from each end. Thecoupling housing 10 is designed with flanges 106, by means of which thecoupling 1 can be attached to an installation opening (not illustrated).A connection piece 13 can be latched onto the coupling housing 10. Thelength of the connection piece 13 may be selected here such that thereis no blockage of access to the grip region 22 provided on the plug-inconnector 2 in the plugged-in state. The plug-in connector 2 isdesigned, for assisting guidance in the coupling housing 10, with atongue 21, which can be introduced into a complementary groove 101 onthe coupling housing 10 and into a groove 131 on the connection piece13.

FIG. 2 shows a section through the coupling 1 and the plug-in connector2. The designations here correspond to FIG. 1. A sleeve mount 11 with asleeve 12 is mounted in the coupling housing 10. The plug-in connector 2is designed with a ferrule 23 at its free end. Two plug-in connectors 2which are to be connected come into contact in the sleeve 12 via the endsurfaces of the ferrules 23, with the result that light waves can betransmitted via the fiber-optic cables formed with the plug-inconnectors 2. With a plug-in connector 2 plugged in on one side, theemission of light waves from a sleeve opening 121 has to be prevented.For this purpose, the sleeve opening 121 can be covered via a leafspring 141. The leaf spring 141 may be selected to be very thin, withthe result that, with the plug-in connector 2 placed in position, saidspring is in close abutment in a depression of the housing wall and doesnot obstruct the plug-in connector 2 from being accommodated.

FIG. 3 shows a perspective illustration of the coupling 1. Thedesignations here correspond to FIGS. 1 and 2. The connection piece 13can be latched onto the coupling housing 10. For the latching fastening,the connection piece 13 is designed with latching tongues 134, whichhave through-passages 135. The coupling housing 10 is designed, on thecontact surfaces 104 of the latching fastening, with latching noses 105,which latch into the through-passages 135. The connection piece 13 doesnot change the width and depth of the coupling 1, with the result thatthe tasks of attaching the coupling to a front panel (not illustrated)and of adding on further couplings are not adversely affected. It isalso possible, in principle, for the connection piece 13 to be designedwith latching noses and the coupling housing 10 to be designed withthrough-passages.

FIG. 4 shows the connection piece 13 schematically. The designationshere correspond to FIGS. 1 to 3. The connection piece 13 may be attachedto the coupling housing 10 (not illustrated) by means of centering pins132, which engage in complementary bores 102 (see FIG. 3) in thecoupling housing 10. The through-passages 135 and the complementarylatching noses 105 are offset vertically in relation to one another.This makes it possible for the latching noses 105 to be formedstraightforwardly in the coupling housing 10, which is illustrated inFIG. 1. However, other shapes and arrangements of the latching noses 105are conceivable. It is also conceivable for the latching tongues 134,rather than extending over the entire width of the connection piece 13,only to cover a region around the latching noses 105 in each case.Additional latching fastenings on the two remaining side surfaces arelikewise conceivable. However, an additional latching fastening must notconceal the groove 131, which is provided for orienting and/orpositioning the plug-in connectors 2, or obstruct the movement of theleaf spring 141, which is provided tangentially to the side surface 136.The latching fastening illustrated, comprising two latching tongues onmutually opposite housing walls, is thus particularly advantageous.

FIG. 5 shows a covering 14 designed with leaf spring 141 and wings 142.The covering 14 is attached to the coupling 1 by means of the wings 142.The size of the wings 142 here is limited by the outer dimensions of thecoupling 1. In principle, however, it is also possible for the leafspring 141 to be attached directly via a tangential extension of theleaf spring.

FIGS. 6( a)-(c) show, schematically, different points in time during aplug-in process. FIG. 6( a) shows the beginning of the plug-in process.At this point in time, the leaf spring 141 is not subjected to loadingand covers the sleeve opening 121. The leaf spring 141 is designed witha curvature which, at one end, runs tangentially to the side surface136. The ferrule 23 of the plug-in connector 2 is worked in a highlyprecise manner and is thus very sensitive. For this reason and due to arisk of contamination, for example, by metal abrasion, the ferrule 23must not come into contact with the leaf spring 141 during the plug-inprocess. The curvature of the leaf spring 141 thus has to be adapted inaccordance with the geometry of the plug-in connector 2. FIG. 6( b)shows the displacement of the leaf spring 141 by a relatively widetermination surface 24 of the plug-in connector 2. A sufficient spacingbetween the ferrule 2 and the leaf spring 141 is ensured here.Laser-beam emission from the coupling housing 10 in the axial directionon account of the sleeve opening 121 being released is prevented by theplug-in connector 2. FIG. 6( c) shows the end of the plug-in operation.The plug-in connector 2 is accommodated in the coupling 1 by latchingmeans. The leaf spring 141 here has been displaced into the depressionof the housing wall by the plug-in connector 2. The very thinconfiguration of the leaf spring 141 causes it to fit very snugly intothe depression of the housing wall. Fitting the cover 14 for protectionagainst the emission of laser radiation thus does not require eitherplug-in connectors 2 provided to be changed or the size of the couplinghousing 10 to be increased.

The protective device described only provides protection against theemission of harmful laser radiation. In most cases, this device does notprovide sufficient protection against the penetration of dust and othercontaminants into the sleeve 12. For additional dust protection when theplug-in connector 2 is subjected to pulling, use has to be made, forexample, of a dust-protection cap 3 illustrated in FIG. 7. Thedust-protection cap 3 is designed with a cylinder 31 by means of whichthe cap can be accommodated by the sleeve mount 11, illustrated in FIG.2 for example, of the coupling 1. In the case of such a dust-protectionconfiguration, the sleeve 12 is sealed precisely at the criticallocation. The diameter of the cylinder 31 is only dependent on thegeometry of the sleeve mount 11, and is thus not dependent on the use ofthe connection piece 13. The dust-protection cap 3 can be aligned by atongue 32. The tongue 32 here engages in the groove 101, illustrated inFIG. 1, of a coupling housing 10 and, if a connection piece 13 is used,also in the groove 131. The length of the tongue 32 here does not haveto correspond either to the length of the groove 101 or of the grooves101 and 131, since no sealing is required there. In addition, it is alsoconceivable to provide dust protection by a cap which seals over the endsides of the coupling housing 10 and/or of the connection piece 13. Theadvantage with sealing over the end sides is that the entire couplinginterior is protected. In order to ensure that the interior is sealed,the groove 101 or the grooves 101 and 131 has/have to be closed bycorresponding tongues on the cap. The configuration of the cap is thusno longer dependent on the configuration of the coupling 1, illustratedin FIG. 1, with or without a connection piece 13. That end of the dustprotector 3 which is directed away from the coupling 1 is designed witha fixing means 33. Via the fixing means 33, the withdrawndust-protection cap 3 can be fastened on a cable of a plug-in connectoraccommodated by the coupling 1. The fixing means 33 comprises apivotable cover 331, which is designed with a latching hook 334, and agroove 333, which complements the latching hook 334. The latching hook334 here may be designed such that different latching positions may beassumed when the cover 331 is closed. The fiber-optic cable can bepositioned in one of the bores 335 when the cover 331 has been swungopen. The bores 335 have different radii, with the result that thedust-protection cap 3 can be fixed on cables with a wide range ofdifferent diameters. The outwardly oriented surface 332 of the cover 331here provides a good inscription surface, which is easily accessiblewhen the coupling 1 is attached to a front panel.

FIG. 8 shows a second embodiment of a fixing means 33 on thedust-protection cap 3. The designations here correspond to FIG. 7. Inthe second embodiment, the fixing means 33 is designed with a latchingconnection 34 into which the fiber-optic cable can be latched. Thelatching connection 34 has bores 341 of different diameters, with theresult that they can be plugged onto a multiplicity of different cablediameters. Also conceivable instead of the bores 341 are sawtooth-likeformations, by means of which different cables can be fixed and/orclamped in. If the plug-in direction of the latching connection 34coincides with the axis of the cylinder 41, a possible inscriptionsurface is dispensed with. However, fixing means which allow theinscription surface to be maintained are to be used in preference. Thedesign of the latching connection 34, with a plug-in directionperpendicular to the axis of the cylinder 31, which is illustrated inFIG. 8 is thus advantageous. This second embodiment of the fixing means33 can be produced in one piece, and thus cost-effectively. Thestraightforward latching onto a cable is also advantageous. Furtherembodiments of the fixing means 33, for example fixing on the couplinghousing by a chain or a flexible strap or by latching or plugging ontothe coupling housing, are likewise conceivable.

Designing the coupling with a protective device according to theinvention and with a dust protector means that, when the plug issubjected to pulling, the coupling is protected against the penetrationof contaminants and the environment is protected against the emission oflaser radiation. The protective device and the dust protector, however,are not mutually dependent.

LIST OF DESIGNATIONS

-   1 Coupling-   10 Coupling housing-   101 Groove-   102 Bore-   104 Contact surface-   105 Latching nose-   106 Flange-   11 Sleeve mount-   12 Sleeve-   121 Sleeve opening-   13 Connection piece-   131 Groove-   132 Centering pin-   134 Latching tongue-   135 Though-passage-   136 Side surface-   14 Covering-   141 Leaf spring-   142 Wing-   2 Plug-in connector-   21 Tongue-   22 Grip region-   23 Ferrule-   24 Termination surface-   3 Dust-protection cap-   31 Cylinder-   32 Tongue-   33 Fixing means-   331 Cover-   332 Inscription surface-   333 Groove-   334 Latching hook-   335 Bore-   34 Latching connection-   341 Bore

1. A coupling for accommodating at least two plug-in connectors whichare connected to fiber-optic cables, comprising: a coupling housingincluding a sleeve having a sleeve opening; a connection piececonfigured to couple to the coupling housing, the connection piecehaving an inner surface; and at least one moveable covering, which isassigned to the sleeve opening, wherein the covering, in a firstposition, covers the sleeve opening and, by the introduction of aplug-in connector, can be moved into a second position, in which thecovering releases the sleeve opening, the covering comprising a bentmetallic leaf spring, the leaf spring biased into the first positionuntil subjected to loading, wherein a ferrule of the plug-in connectordoes not come into contact with the leaf spring at any point in time asthe covering is moved to the second position, and wherein the coveringincludes wings that extend from the covering over an inner surface ofthe connection piece to secure the covering to the connection piece, thecovering being planar when the covering is moved into the secondposition, and wherein the wings include tabs that are coplanar therewithand that extend toward the coupling housing, and wherein the wingsdefine cutouts between the covering and the tabs such that the tabs arecoupled to the covering by reduced width planar extensions.
 2. Thecoupling as claimed in claim 1, further comprising centering pinsconfigured to form a connection between the connection piece and thecoupling housing.
 3. The coupling as claimed in claim 1, wherein thecovering is fastened on the connection piece by hot stamping.
 4. Thecoupling as claimed in claim 1, wherein the connection piece is designedas a plastic part, and the covering can be connected to the connectionpiece by injection-molding encapsulation.
 5. The coupling as claimed inclaim 1, wherein the connection piece is fonned from sheet-metal.
 6. Thecoupling as claimed in claim 1, wherein the leaf spring, in the secondposition, rests in a depression of the housing wall.
 7. The coupling asclaimed in claim 1, wherein the connection piece includes latching meansand can be monnted onto the coupling housing via the latch.
 8. Thecoupling as claimed in claim 7, wherein the latching means of theconnection piece includes through-passages in latching tongues andlatching means of the coupling housing includes latching noses.
 9. Acoupling arrangement comprising: a coupling housing configured toaccommodate a first plug-in connector at a first end of the couplinghousing and a second plug-in connector at a second, opposite end of thecoupling housing, each plug-in connector including a ferrule throughwhich light can be emitted; and a first connection piece configured tocouple to the second end of the coupling housing, the first connectionpiece having an inner surface from which a first portion of a coveringcurves upwardly in a first position and along which a second portion ofthe covering extends from a first distal end to a second distal end tosecure the covering to the first connection piece, the second portion ofthe covering being pianar from the first distal end to the second distalend, the first portion of the covering being moveable from the firstposition, in which the first portion inhibits light emitted from thefirst plug-in connector from reaching the second end of the couplinghousing, to a second position, in which the first portion of thecovering does not inhibit light emitted from the first plug-in connectorfrom reaching the second end of the coupling housing, the second portionof the covering including a first reduced width planar section couplinga first tab to the first portion of the covering, the first tabextending coplanar with the second portion from the first distal end ofthe second portion toward the coupling housing, and the second portionof the covering including a second reduced width planar section couplinga second tab to the first portion of the covering, the second tabextending coplanar with the second portion from the second distal end ofthe second portion toward the coupling housing; wherein the coveringmoves from the first position to the second position by insertion of thesecond plug-in connector at the second end of the coupling housing, andwherein a ferrule of the second plug-in connector does not contact thefirst portion of the covering when the second plug-in connector isinserted.
 10. The coupling arrangement of claim 9, wherein the covering,in the second position, rests within a depression in an inner surface ofthe coupling housing.
 11. The coupling arrangement of claim 9, furthercomprising: a second connection piece configured to couple to the firstend of the coupling housing, the second connection piece having an innerwall; a second covering curving upwardly from the inner surface of thesecond connection piece, the second covering being moveable from a firstposition, in which the second covering inhibits light emitted from theferrule of the second plug-in connector from reaching the first end ofthe coupling housing, to a second position, in which the second coveringdoes not inhibit light emitted from the ferrule of the second plug-inconnector from reaching the first end of the coupling housing.
 12. Thecoupling arrangement of claim 9, wherein the covering comprises ametallic leaf spring.
 13. A connection piece for coupling to a couplinghousing, the coupling housing configured to accommodate a first plug-inconnector at a first end of the coupling housing and to accommodate asecond plug-in connector at a second, opposite end of the couplinghousing, the connection piece comprising: a body including twospaced-apart sides interconnected by a base, the base having an innersurface and an opposite outer surface, the body defining an open frontand an open rear, the open rear of the body being configured to coupleto a first end of the coupling housing; a covering coupled to the body,a first portion of the covering extending along the inner surface of thebase between the two spaced-apart sides of the body, and a secondportion of the covering curving upwardly from the inner surface of thebase and towards the open rear, the second portion, when in a firstposition, being configured to inhibit light emitted from the secondplug-in connector from exiting the adapter, wherein inserting the firstplug-in connector moves the covering to a second position enablingoptical communication between the second plug-in connector and the firstplug-in connector; and first and second wings coupled to the innersurface of the body, the first and second wings being coplanar with thefirst portion of the covering, the first wing extending from the firstportion of the covering along the inner surface of the body to a firstof the spaced-apart sides, the second wing extending from the firstportion of the covering along the inner surface of the body to a secondof the spaced apart sides, the first and second wings including tabsprojecting along the inner surface of the body towards the open rear ofthe body, the tabs being coplanar with the first portion of thecovering, the first and second wings defining cutouts between the tabsand the first portion of the covering.
 14. The connection piece of claim13, wherein the body is formed from plastic, and the covering couples tothe body through injection-molding encapsulation.
 15. The connectionpiece of claim 13, wherein the covering is coupled to the body by hotstamping.
 16. The connection piece of claim 13, wherein the coveringcomprises a metallic leaf spring.
 17. The connection piece of claim 13,wherein the covering is formed integrally with the body.
 18. Theconnection piece of claim 13, wherein the connection piece is formedfrom sheet-metal.